25 juin 2019
Richard C.P. Wilson, « Half mile N. of North Star Mine. Semidense shrub-tree type of ponderosa pine. Arctostaphylos viscida, Ceanothus integerrimus. Assoc. spp.: Ceanothus prostratus, Chamaebatia foliolosa. Nevada County. », Berkeley Library Digital Collections, ID : 10670/1.xq18sa